The \(B_{c}\)  meson, laying below \(BD\)  threshold, can decay only
via the weak interaction. Its decay modes can be divided into
three types [1]}, [2]}:
(1) the \(c\)  quark decays while the \(b\)  quark as a spectator;
(2) the \(b\)  quark decays while the \(c\)  quark as a spectator;
(3) the annihilation channel.
The \(c\)  quark decay modes [the type (1)] are responsible for
about \(70\%\)  of the width of \(B_{c}\)  meson [3]}.
This type of decay process, although very challenging to
experiments, has recently been observed in the \(B_{c}\)  \({\rightarrow }\) 
\(B_{s}{\pi }\)  mode with significance in excess of 5 standard
deviations by the LHCb collaboration [4]}.
The \(b\)  quark decay modes [the type (2)] account for about
\(20\%\)  of the width of \(B_{c}\)  meson [5]}. The
\(b\)  \({\rightarrow }\)  \(c\)  transition offers a well-reconstructed
experimental signature at the Tevatron and LHC,
for example, in the decay modes of
\(B_{c}^{+}\)  \({\rightarrow }\)  \(J/{\psi }{\pi }^{+}\) 
[6]}, [7]}, [8]},
\({\psi }(2S){\pi }^{+}\)  [9]},
\(J/{\psi }D_{s}^{(\ast )+}\)  [10]},
\(J/{\psi }K^{+}K^{-}{\pi }^{+}\)  [11]},
\(J/{\psi }{\pi }^{+}{\pi }^{-}{\pi }^{+}\)  [12]},
\(J/{\psi }e^{+}{\nu }_{e}\)  [13]}
and so on.
The weak annihilation mode [the type (3)] is estimated
to take \(10\%\)  shares of the width of \(B_{c}\)  meson
[5]}. The pure weak annihilation decay to
two light mesons, \(B_{c}\)  \({\rightarrow }\)  \(u\)  \(+\)  \(d\) , is so highly
helicity-suppressed that there is little probability of
detecting the charmless and/or bottomless hadronic
decays \(B_{c}\)  \({\rightarrow }\)  \(PP\) , \(PV\) , \(VV\)  [15]},
where \(P\)  and \(V\)  denote the lightest \(SU(3)\)  pseudoscalar
and vector mesons, respectively;
and to date, no corresponding measurements exist.
